You have either given it a title, or an image, not both. You should use the
JButton butoEtnies = new JButton("Etnies", /*Here goes the icon*/);
Or you can also try:
JButton butoEtnies = new JButton("Etnies");
butoEtnies.setIcon(/*Here goes the icon*/);
Besides, here's the Java API for JButton
EDIT #2
Next, provides an particular actionlistener for the butoEtnies button, in which you do not need to specify an ID or a title for the getActionCommand
JButton butoEtnies = new JButton (/*path to icon*/);
butoEtnies.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//You can code whatever you want here
System.out.println("butoEtnies clicked");
}
});